Device and method for transporting separate substrates

ABSTRACT

A device and a method for separately transporting substances are provided. The device and method according to the invention can especially be used in connection with an unit for producing DVDs. Preferably, the device according to the invention has for each substrate an input station, a processing station and an output station, which stations are arranged on the circular arc at given distances α. Furthermore, grippers are provided, which are arranged on said circular arc at given distances α and can be simultaneously rotated around an axis through the center of said circle through an angle β. Each gripper transports one substrate to the processing and output stations in a rotational movement. It is the advantage of the invention that the mixing-up of substrates is avoided.

This application is the national phase of international application PCT/EP98/03094 filed May 26, 1998 which designated the U.S.

The invention relates to a device and a method for separatelytransporting substrates and can be used especially in the production ofDVDs (digital versatile disks).

Especially in the production of DVDs it is of particular importance thattwo substrates, which are bonded to form a DVD, are kept apart duringtransport and are not mixed up.

In known transporting systems for the DVD process (Cube of the companyBalzers, cf. DE-C2-42 35 677) the substrates for the DVD are suppliedthrough one single lock station. In this case there is a risk that thedifferent substrates are mixed up.

U.S. Pat. No. 4,969,790 discloses a device and a method for coatingsubstrates in a vacuum chamber, wherein a rotatable substrate holderbears a plurality of substrate receivers adapted to transport substrateson a circular path from one lock station to an associated coatingstation and back to the same respective lock station.

Moreover, the prospectus Speedline, DVD-Speedline plus, Leybold SystemsGmbH, 2/97 discloses a transporting system in which different substratesare transported by a rotational movement to different processingstations.

DE-C1-196 06 764 discloses a device for gripping, holding and/ortransporting substrates. A substrate is transported by means of grippingelements from an input station to a plurality of processing stationsarranged in a line or circle. A plurality of gripping arms can beadjusted in a horizontal and/or vertical direction. Some grippingelements can be adjusted together in a horizontal and/or verticaldirection, and at least one gripping arm can be adjusted independentlyof the other gripping arms in at least one of the movement directions.

It is an object of the present invention to provide a device and amethod for separately transporting substrates, wherein mixing-up of thesubstrates is reliably prevented.

The object is achieved with the features of the claims.

In achieving this object, the invention starts out from the followingbasic ideas.

Two input stations are arranged on a circular arc at a given angulardistance α. Moreover, at least two processing stations, which are spacedfrom each other by the given angle α, can be provided on the arc of thecircle. Grippers are provided on the same arc of the circle at the givendistance α and can be simultaneously rotated around an axis through thecenter of said circle through an angle β. Two grippers simultaneouslytake one substrate each and transport the substrates to the processingstations, e.g. by rotating the gripping arrangement through 120°. Thenthe grippers can transport the different substrates to two outputstations. The grippers can take up new substrates so that the transportstep can be repeated. It is also possible to transport the substratesdirectly to the output stations thereby avoiding the processingstations, e.g. by changing the direction of rotation or, if thedirection of rotation is maintained, by a rotation through 240°.Preferably, the grippers make a pendulum movement. Two gripperstransport the substrates from the input stations to the processingstations and two grippers from the processing stations to the outputstations in a reciprocating movement.

The advantages of the present invention reside in that a mixing-up ofthe substrates is avoided.

In the following, the invention is explained in more detail on the basisof the drawings in which

FIG. 1 is a basic drawing of the device of the present invention,

FIG. 2 is a top view of an embodiment of the present invention inconnection with an arrangement for producing DVDs.

FIG. 1 shows a top view of the basic construction of the device of thepresent invention. Two separate transport paths 1′, 7′ and 1″, 7″ areconnected with each other by a transporting means 4. The devicecomprises two input stations 2′, 2″, two processing stations 5′, 5″ andtwo output stations 6′, 6″. The transporting means 4 comprises at leasttwo grippers 11, 12 which are rotatable around a rotational axis 3 andwhich are arranged on a circular arc 8 at a given angular distance α bymeans of arms 20. Between the two input stations 2′, 2″, the twoprocessing stations 5′, 5″ and the two output stations 6′, 6″, there isthe same given angular distance α. The substrates 1′ and 1″ taken by therespective grippers 11 and 12 at the respective input stations 2′ and 2″are transported by a rotational movement through an angle β to therespective processing stations 5′ and 5″ and/or the respective outputstations 6′ and 6″. The rotational angle β depends on the distance ofthe different stations. However, it is preferably larger than the angleα between two equal stations. Thus, even more than the three stationpairs as shown in FIG. 1 may be arranged on a single circular arc.

FIG. 2 shows an embodiment of the invention in connection with anarrangement for producing DVDs. Substrates 15′ and 15″ are transportedfrom respective magazines or spindles 9′ and 9″ via respective transportpaths 10′ and 10″ to the respective input stations 2′ and 2″. The inputstations are arranged on the circular arc 8 at a distance of preferably60°. Moreover, two processing stations 5′ and 5″ and two output stations6′ and 6″, which are spaced from each other and from the input stationsby 60°, are arranged on the same circle. A transporting means 4 whichcan be rotated around an axis 3 of the circular arc 8 comprises grippers11, 12, 13 and 14 for transporting the substrates 15′ and 15″ on thecircle 8. In FIG. 2 the grippers 11 and 12 take over the substrates 15″and 15′, respectively, in the respective processing stations 5″ and 5′,and the grippers 14 and 13 take over the substrates 15′ and 15″,respectively, in the respective input stations 2′ and 2″. Thus, it isguaranteed that substrates 15′ from the transport path 10′ can only betransported to the processing station 5′ and substrates 15″ from thetransport path 10″ only to the processing station 5″. From theprocessing stations 5″ and 5′, the respective grippers 11 and 12 thentransport the substrates to the respective output stations 6″ and 6′.The grippers 11 and 12, which became free, are then rotated back to therespective processing stations 5″ and 5′ and, at the same time, thegrippers 13 and 14 are rotated back to the respective input stations 2″and 2′. In this connection, the grippers carry out a reciprocating(pendulum) movement. In this way, grippers being optimally adapted tothe respective situation can be used. However, it is also possible tostandardize the stations and to use a standardized type of gripper.Then, the grippers can move along the circle and, for example, threegripper pairs can be used.

In the arrangement according to FIG. 2 the processing stations 5′ and 5″are for example cathode sputtering units in which the substrates 15′ and15″ are coated. The grippers 13 and 14 supply the respective substrates15″ and 15′ to the lock stations (not shown) of the correspondingcathode sputtering units in which the substrates 15′ are coated with afully reflecting layer of e.g. aluminum and the substrates 15″ with asemi-transparent layer, e.g. gold. After a cyclical course through thecathode sputtering unit, the substrates 15″ and 15′ are again taken upby the respective grippers 11 and 12 and transported to the outputstations 6″ and 6′. A turning device 16 is arranged behind the outputstation 6″, and a rotary table 17 is arranged behind the output station6′. The rotary table 17 transports the substrate 15′ into the area 16 aof the turning device 16 which places the turned substrate 15″ onto thesubstrate 15′. Then the two substrates are bonded. By a furthertransporting means 18, the bonded substrates 15 (consisting ofsubstrates 15′ and 15″) are transported into a drying means 19 forcuring the bonding layer (e.g. by UV radiation), then by a transportingmeans 21 to a turning station 22 and a test station (scanning means) 23and finally to the output station 24.

In the turning station 22 the bonded substrate 15 is turned upside downso that the half 15″ lies on the bottom. Then the substrate istransported to the test station 23. The turning station 22 is providedto allow, depending on the DVD type, scanning through the substrate 15″and the transparent semi-transparent layer, e.g. gold layer, from thebottom if, as shown in the example of FIG. 2, the DVD comprises on itstop a substrate 15″ having a gold layer, for drying the bond layer inthe drying means 19 from the top through the semi-transparent gold layerwith low energy and thus time requirements. The turning station 22 isnot used if the upper substrate 15″ is not coated, as it is the case inother DVDs (type DVD5), and if the lower substrate 15′ is coated withaluminum. In this case the DVD is already in the position required forscanning in the test station. The turning station 22 which can be usedoptionally thus increases flexibility and usability of an unit forproducing different DVDs, e.g. DVD9 or DVD5.

Thus, the use of a turning station which can be used optionally is alsoper se in general an essential inventive feature in the production ofDVDs.

Instead of being connected with the magazines (spindles) 9′ and 9″, therespective transport paths 10′ and 10″ can also be connected directlywith an injection molding machine for producing the respectivesubstrates 15′ and 15″.

If no processing steps are required in the processing stations 5′ and5″, e.g. in case the two substrates 15′ and 15″ are produced and coatedoff-line and are then stored temporarily in the two spindles 9′ and 9″,respectively, the substrates 15′ and 15″ can possibly be transporteddirectly to the respective output stations 6′ and 6″ by changing thedirection of rotation.

By means of the device according to the present invention the substratescan easily be transported on two separate transport paths without therisk of mixing them up, wherein for retrofitting the unit, theprocessing stations 5′ and 5″ can be easily incorporated later, ifrequired.

It is also possible to combine the transporting means 4 together withthe bonding means 16 a, the transporting means 18, the drying station19, the turning station 22 and the test station 23 with any desirednumber of other upstream-located means (e.g. sputtering unit, injectionmolding unit) and processing stations in accordance with the unitconstruction principle.

What is claimed is:
 1. A device for producing a substrate compositeconsisting of two substrates bonded together with an intermediate bondlayer; said device comprising: (a) first and second input stations (2″,2′, respectively) arranged on a circular arc (8), said input stationsbeing spaced apart by an angular distance α and each respectivelysupplying a respective one of a first and a second substrate (15″, 15′)for a first and a second substrate composite half, (b) at least firstand second processing stations (5″, 5′) arranged on the circular arc(8), said processing stations being spaced apart by the angular distanceα, (c) first and second output stations (6″, 6′, respectively) arrangedon the circular arc (8), said output stations being spaced apart by theangular distance α, for receiving the first and the second substrates,respectively, after processing, wherein the first output station (6″)comprises a device for turning the first substrate and placing it ontothe second substrate, (d) a first transporting means (4) fortransporting the first and second substrates on the circular arc (8) andcomprising at least two grippers (11 and 12) which can be rotated on thecircular arc through an angle β, wherein each of the grippers (11 and12) transports a respective one of the first and second substrates froma respective input station (2″ and 2′) to a respective processingstation (5″ and 5′) and to a respective output station (6″ and 6′), (e)a bonding station for bonding the first and second substrates with abond layer disposed intermediate the first and second substrates to forma substrate composite, (f) a drying station (19) for curing the bondlayer, (g) a turning station (22) for turning the substrate composite,(h) a test station (23) for testing the substrate composite, (i) anoutput station (24) for the substrate composite, and (j) a secondtransporting means (18) for transporting the substrate composite betweenthe stations defined in clauses (e) to (i).
 2. The device according toclaim 1, wherein the processing stations (5″ and 5′) are cathodesputtering units.
 3. The device according to claim 1, wherein the secondoutput station (6′) comprises a rotary table which transports the secondsubstrate to the turning device of the first output station (6″).
 4. Thedevice according to claim 1, further comprising a third transportingmeans (21) for transporting the substrate composite between the dryingstation and the turning station.
 5. The device according to claim 1,wherein the first and the second input stations (2″ and 2′,respectively) are connected with magazines or spindles for thesubstrates or with an injection molding unit for the substrates via atransport path.
 6. The device according to claim 1, wherein therotational angle β of the grippers of the first transporting means (4)is larger than the angular distance α.
 7. The device according to claim6, wherein the angular distance α is 60°.
 8. The device according toclaim 7, wherein each input station is spaced from a respectiveprocessing station and a respective output station by the angle β, whichis 120°.
 9. The device according to claim 1, wherein the firsttransporting means (4) comprises first, second, third and fourthgrippers (11, 12, 13, 14) arranged at an angular distance from oneanother, wherein between the first and the second grippers (11 and 12,respectively) and between the third and the fourth grippers (13 and 14,respectively) there is the angular distance α, and between the first andthe third grippers (11 and 13, respectively) and between the second andthe fourth grippers (12 and 14, respectively) there is the angulardistance β.
 10. The device according to claim 9, wherein the substratecomposite is a DVD and the first and the second substrates (15′, 15″)are the halves of a DVD.
 11. The device according to claim 1, whereinthe first transporting means (4) comprises six grippers each beingarranged at an angular distance of 60° from one another.
 12. The deviceaccording to claim 1, wherein the substrate composite is a DVD and thefirst and the second substrates (15′, 15″) are the halves of a DVD. 13.A method for producing a substrate composite using the device accordingto claim 1; the method comprising: (a) transporting a first and a secondsubstrate (15″, 15′) for a first and a second substrate composite halfto the first and the second input stations (2″ and 2′, respectively),respectively, (b) transporting the first and the second substrates bymeans of the respective grippers (11 and 12) to the first and the secondprocessing stations (5″ and 5′), respectively, (c) selectively coatingthe first and the second substrates, (d) transporting the firstsubstrate and the second substrate by means of the respective grippers(11 and 12) to the first and the second output stations (6″ and 6′,respectively), respectively, (e) turning the first substrate (15″), (f)transporting the second substrate (15′) beneath the first substrate(15″), (g) bonding the first and the second substrates with a bond layerdisposed intermediate the first and second substrates to form asubstrate composite, (h) transporting the substrate composite to thedrying station (19), (i) curing the bond layer, (j) transporting thesubstrate composite to the turning station (22) for turning thesubstrate composite, (k) transporting the substrate composite to thetest station (23), (l) testing the substrate composite, and (m)transporting the substrate composite to the output station (24).
 14. Themethod according to claim 13 further comprising turning the substratecomposite after (j) and before (k).
 15. The method according to claim 13wherein operation of the turning station (22) in (j) further comprisesselectively turning the substrate composite only when a lower half of anarriving substrate composite is not coated.
 16. The method according toclaim 15, wherein said testing the substrate composite in (l) comprisesscanning the substrate composite from the bottom.
 17. A method of usingthe device according to claim 9 for producing a substrate composite,wherein the processing stations are cathode sputtering units, the methodcomprising: (a) transporting first and second substrates (15″ and 15′)on transport paths (10″ and 10′) to the respective input stations (2″and 2′), (b) transporting the first and the second substrates (15″ and15′, respectively) by means of the third and the forth grippers (13 and14, respectively) to respective cathode sputtering units (5″ and 5′) byrotating the transporting means through 120°, (c) selectively coatingthe first substrate (15″) in the first cathode sputtering unit (5″) andselectively coating the second substrate (15′) in the second cathodesputtering unit (5′), (d) transporting the two substrates (15″ and 15′)by means of the first and second grippers (11 and 12, respectively) tothe first output station (6″) being arranged upstream of a turningdevice (16), and to the second output station (6′) being arranged on arotary table (17), respectively, (e) turning the first substrate (15″)in the turning device (16) and placing the second substrate (15′) ontothe first substrate (15″), (f) bonding the substrates (15′ and 15″),with a bond layer disposed between the substrates (15′ and 15″), in thebonding station to form the substrate composite, (g) transporting thesubstrate composite by means of the second transporting means (18) tothe drying station (19), (h) drying the substrate composite to cure thebond layer, and (i) transporting the substrate composite to the teststation (23) and to the output station (24).
 18. The method according toclaim 17, wherein between (h) and (i) the substrate composite is turnedin a turning station (22) so that the second substrate (15′) lies on thebottom and it is thus possible to scan the substrate composite from thebottom in the test station (23).
 19. The method according to claim 17,wherein the grippers (11, 12, 13, 14) circulate on the circular arc (8)in one direction and each pair of grippers (11, 12 and 13, 14) servesall stations (2′, 2″; 5′, 5″; 6′, 6″).
 20. The method according to claim17, wherein the substrate composite is a DVD and the first and secondsubstrates are the halves of a DVD.